The sintering process consists in thermal treatment of a powder or compacted metal, ceramic or plastic at a temperature lower than the fusion temperature of the mix, which increases the strength and the resistance of the part due to the strong bonds produced between the particles.
On the other hand, the machining process, particularly three-dimensional machining, mainly consists in cutting the machined material with a rotary tool equipped with several blades, known as teeth, lips or small plates made of hard metal. These follow forward movements in almost any direction that the workbench can move in, programmed from the workbench on which the part being machined is fastened.
In manufacturing processes of parts that require a high degree of precision and expensive materials, the sintering process has obtained an extraordinary reduction in costs and, although the tolerance and precision obtained are acceptable, these could be improved since they are conditioned by the size of the powder particles used in the sintering process. On the other hand, the amount of discarded material in machining processes such as milling is relatively large, as well as the time invested in the process, which considerably increases the cost of the manufacturing process. However, the precision obtained is quite good.
Although the manufacture of parts by means of the sintering process obtains complex parts easily, inexpensively and efficiently, the geometry of these parts may require a high degree of precision, especially in the areas that need a perfect mechanical fit with other parts. In addition, the parts manufactured so far may require that the surface of these parts have a different grade of finish in order to obtain future advantages derived from the different surface finish.
Therefore, it is the object of this invention to develop parts that can be manufactured by means of the sintering process and to obtain different degrees of precision in different areas, as well as to obtain the advantages derived from their surface finishes.
Also on the other hand, it is the object of this invention to develop a high-precision parts manufacturing method that combines the advantages of the sintering process and three-dimensional machining in which the costs are as low as possible while the precision and tolerance obtained are the best possible.